Plague researcher dies in Siberia, dozens quarantined after infection scare

A laboratory worker at a plague research institute in Siberia has died, prompting authorities to quarantine dozens of people and dispatch Russia's health watchdog head to the Irkutsk region. The cause of death remains undisclosed, though officials say the situation is under control. The 28-year-old woman, named locally as Darya Shipilova, died of pneumonia of undetermined origin, according to regional governor Igor Kobzev. Tests found no microorganisms linked to her professional work, and no new cases have been reported among institute staff since her death. Plague is endemic to Siberia, where Yersinia pestis bacteria exist in wild mammals, though human cases are rare. Pneumonic plague, the most contagious form, can be fatal if untreated. US Secretary of State Marco Rubio said Washington is monitoring the situation but sees no cause for alarm.